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<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<body>
  <script>
    var grade = prompt("请输入分数");
    grade = parseInt(grade / 10);
    if (grade === 10 || grade === 9) {
      alert("你的成绩等级为优秀");
    } else if (grade === 8 || grade === 7 || grade === 6) {
      alert("你的成绩等级为良好");
    } else {
      alert("你的成绩等级为不及格，继续加油哦！");
    }
  </script>
</body>

</html>